Filter Cleaning System for a Vacuum Cleaner

ABSTRACT

A vacuum cleaner dust separation unit having a cyclone chamber ( 113 ) and a dust collection chamber ( 115 ). The cyclone chamber ( 113 ) extends along a longitudinal axis ( 398 ), and has an air inlet ( 183 ), an air outlet ( 408 ), an inlet wall ( 396 ) between the air inlet ( 183 ) and the air outlet ( 408 ), and one or more air passages ( 404 ) through the inlet wall ( 396 ). The dust collection chamber ( 115 ) is adapted to receive dirt from the cyclone chamber ( 113 ). In one aspect, the inlet wall ( 396 ) comprises an elliptical wall that is located adjacent the air inlet ( 182 ) and angled relative to the longitudinal axis ( 398 ). In another aspect, the cyclone chamber ( 113 ) has an end wall ( 432 ) located opposite the inlet wall ( 396 ), and a dirt outlet ( 114 ) to the dust collection chamber ( 115 ) located adjacent the end wall ( 432 ), and the end wall ( 432 ) has a recessed portion ( 438 ) surrounding an extended portion ( 436 ) that protrudes into the cyclone chamber ( 113 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage entry of PCT application no. PCT/US2007/014263 (filed Jun. 15, 2007), which is a continuation-in-part of U.S. patent application Ser. No. 10/567,463 (filed under 35 U.S.C. §371(c) on Feb. 7, 2006), which application is a national stage entry of PCT application no. PCT/SE04/01756 (filed Nov. 26, 2004), which PCT application claims priority to Swedish application nos. 0303277-8 (filed Dec. 4, 2003) and 0401183-9 (filed May 6, 2004). This application claims priority to all of the preceding applications, and incorporates them herein by reference.

FIELD OF THE INVENTION

The present invention relates to a vacuum cleaner. More particularly, embodiments of the invention relate to apparatus and methods for cleaning filters used in a vacuum cleaner.

BACKGROUND OF THE INVENTION

Traditional vacuum cleaners usually belong to two different categories called canister cleaners and upright cleaners. The canister vacuum cleaner comprises a housing enclosing an electric fan unit that creates an airflow from a vacuum cleaner nozzle through a tube shaft and a hose and further through a separating system comprising a porous bag collecting the dust before the air reaches the fan and leaves the housing to the ambient air. The upright vacuum cleaner differs from the canister cleaner in that the tube shaft and the hose are eliminated and that the nozzle, which often is provided with a rotating brush, is pivotally connected to the vacuum cleaner housing. The housing encloses the fan unit and the air pervious dust bag and is provided with a handle to move the complete vacuum cleaner on the floor.

In order to further clean the air before the air leaves the vacuum cleaners mentioned above, additional filters are arranged after the dust bag as seen in the air flow direction. These filters are usually placed such that they can easily be removed and be replaced by a new filter. As an alternative certain filters might be taken away in order to be cleaned by manual operations or by washing or rinsing the filter in water and/or cleaning agents.

There are also so-called cyclone vacuum cleaners on the market, see for instance EP 00850060.1, that are provided with a different type of dust separation system.

Instead of using an air pervious collecting bag the dust is separated by means of a vortex created in a circular cyclone chamber. The particles are by means of centrifugal action directed outwards from the center of the vortex and are collected in a collecting container, whereas the cleaned air is taken out from the center of the vortex. The clean air is then sucked to the vacuum source and flows out from the vacuum cleaner to the ambient air. Even if the main part of the dust particles that are present in the dust laden air are separated by the cyclone a minor part of the particles follow the clean airflow out of the cyclone. Consequently, for this type of vacuum cleaners there is also a need for filters in the air passages after the cyclone chamber in order to get an efficient cleaning of the air flowing out from the vacuum cleaner.

It is a disadvantage that the operator of all of the vacuum cleaners mentioned above has to remove the filter and replace it or clean it since replacement means that the consumer always has to keep an eye on the consumption of the filter and to buy new filters when necessary whereas cleaning means that the vacuum cleaner can not be used during the washing period and moreover demands for certain cumbersome activities from the operator.

It has also been proposed, see WO 85/02528, to provide a vacuum cleaner with two electrical motors (FIGS. 1-4) each having a filter that is placed in a common dust collecting chamber. In order to clean the filters the airflow through each filter is reversed by means of the other motor. The same publication also shows a vacuum cleaner arrangement (FIGS. 5-6) that is provided with one motor and one main filter and an auxiliary filter the filters also being placed in a common dust collecting chamber. In order to clean the main filter, the airflow is reversed and directed through the auxiliary filter. A clear disadvantage with the first arrangement is the need for two motors whereas there is no indication how to clean the auxiliary filter in the second arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIG. 1 is a schematic view of a vacuum cleaner comprising a first embodiment of the invention. The schematic shows a first filter in an active position and a second filter in an inactive position.

FIG. 2 is a schematic view of a vacuum cleaner comprising a first embodiment of the invention. The schematic shows a first filter in an inactive position and a second filter in an active position.

FIG. 3 is a schematic view of a vacuum cleaner comprising a first embodiment of the invention. The schematic shows the airflow through the vacuum cleaner when a first filter is cleaned.

FIG. 4 is a schematic view of a vacuum cleaner comprising a first embodiment of the invention. The schematic shows the airflow through the vacuum cleaner when a second filter is cleaned.

FIG. 5 is a schematic view of a vacuum cleaner comprising a second embodiment of the invention. The schematic shows a first filter in an active position during an ordinary vacuum cleaning operation and a second filter in an inactive position.

FIG. 6 is a schematic view of a vacuum cleaner comprising a second embodiment of the invention. The schematic shows a filter being cleaned.

FIG. 7 is a schematic view of a vacuum cleaner comprising a further embodiment of the invention.

FIG. 8 is an exploded view of a body of a vacuum cleaner comprising a further embodiment of the invention.

FIG. 9 is a partially cut-away top view of a portion of a filter support structure of an embodiment of the invention.

FIG. 10 is an isometric view of an assembled vacuum cleaner body comprising an embodiment of the invention.

FIG. 11 is a partially exploded, isometric view of a power nozzle, wand, and handle in accordance with an embodiment of the invention.

FIG. 12 is an exploded, isometric view of the handle assembly of FIG. 11.

FIG. 13 is an exploded, isometric view of a hose cuff assembly for use with an embodiment of the invention.

FIG. 14 is a side, plan view of an auxiliary nozzle tool in accordance with an embodiment of the invention.

FIG. 15 is a top, isometric view of the filter module of the embodiment of FIG. 10, shown with the cover open and the filter cartridges removed.

FIG. 16 is an isometric view of the filter and handle assembly of the embodiment of FIG. 10, shown with the filter cartridges attached to the handle.

FIG. 17 is an isometric view of the valve assembly cover and actuating valve mechanism of the embodiment of FIG. 10.

FIG. 18 is a side, plan view of the valve assembly of FIG. 17, as installed in the filter module of FIG. 10, shown in a position for normal surface cleaning.

FIG. 19 is the valve assembly of FIG. 18 with the valve mechanism in a position for filter cleaning.

FIG. 20 is a side, plan view of an end cap assembly for use in a cyclonic dust separation unit in accordance with an embodiment of the invention.

FIG. 21 is a cut-away, side view of a dust separation unit of an embodiment of the invention.

FIG. 22 is a plan view of the dust separation unit of FIG. 21, as seen from a front end of the vacuum body.

FIG. 23 is a plan view of the dust separation unit of FIG. 21, illustrating the underside of the dust separation unit as it would be placed on a vacuum body.

FIG. 24 is a plan view of the end of a the dust separation unit of FIG. 21, shown with the lid removed.

FIG. 25 is a plan view of a lid for use with the dust separation unit of FIG. 21.

FIG. 26 is an isometric view of the vacuum cleaner body of the embodiment of FIG. 10, showing a cradle for accommodating the dust separating unit of FIGS. 20-25.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is intended to convey a thorough understanding of the invention by providing a number of specific embodiments and details involving a vacuum cleaner. It is understood, however, that the invention is not limited to these specific embodiments and details, which are exemplary only. For example, while embodiments of the invention described herein comprise a canister vacuum. However, the invention is not limited to a canister vacuum, but rather, a person having ordinary skill in the art would recognize that the invention can also be applied to upright vacuums, central vacuums, and or other apparatus requiring particle separation from an airflow. It is further understood that one possessing ordinary skill in the art, in light of known systems and methods, would appreciate the use of the invention for its intended purposes and benefits in any number of alternative embodiments.

FIG. 1 schematically shows a vacuum cleaner body 10 that encloses a single vacuum source such as fan unit 11 and a dust separation unit 12. The dust separation unit 12 is of the so called cyclone type and comprises a circular chamber 13 that is provided with a tangential inlet 14 (or a non-tangential inlet with a tangential deflector) for dust laden air and a central outlet 15 for clean air. Due to the airflow, a vortex is created within the chamber 13 and the dust particles are separated from the airflow by means of the centrifugal forces and are thrown into a dust collecting container 16 via an opening 17.

The inlet 14 is via a channel 18 connected to an opening 19 in the vacuum cleaner body that in a conventional way can be connected to a vacuum cleaner nozzle 20 via a hose 21 and a tube shaft 22. The central cyclone outlet 15 is connected to a channel 23 via a valve 24 such that the airflow can be directed to a first or a second section 23 a, 23 b of the channel 23. The sections 23 a and 23 b are via valves 25 and 26 connected to a common channel 27 that by means of a further valve 28 is branched off from the channel 18.

Channel section 23 a ends in a central part of a first tube-shaped filter cartridge 29 that is provided with a grip 30 that is accessible from the outside of the vacuum cleaner. The cartridge 29 is inserted in a first filter space 31, shaped as a filter holder and provided at the vacuum cleaner body, and can easily be removed from the space 31. The filter cartridge 29 is preferably made from a material that can be cleaned manually or by a washing operation.

Channel section 23 b in a corresponding way ends in the central part of a second tube-shaped filter cartridge 32 provided with a grip 33 accessible from the outside of the vacuum cleaner. This cartridge is inserted in a second filter space 34 and has the same design and filter material as the first mentioned cartridge 29.

The first as well as the second filter space 31, 34 offers a free space around each filter cartridge which are connected to a common channel 35 communicating with the fan unit 11. The channel comprises a first section 35 a and a second section 35 b, each being provided with a valve 36 and 37 that can connect the respective section 35 a , 35 b with the ambient air.

The arrangement operates in the following manner. During an ordinary cleaning operation, shown in FIG. 1, the valve 28 is in such a position that the opening to the branched off channel 27 is closed. Dust laden air is taken in through the nozzle 20 and is conveyed through the tube shaft 22, the hose 21 and the channel 18 to the cyclone chamber 13. The major part of the dust particles are separated in the cyclone chamber 13 and are conveyed to the collecting container 16. The clean air with a minor part of smaller particles flows out through the outlet 15 at the center of the cyclone chamber 13 and is by means of the valve 24 directed into the second section 23 b and is by the valve 26 directed further into the central part of the second tubular filter cartridge 32. The air then flows through the filter material in the cartridge, in which the major part of the remaining particles are filtered out, before the air reaches the filter space outside the filter cartridge 32 from which the air flows further into the second section 35 b of the channel 35 before entering into the fan unit 11. The air then escapes from the vacuum cleaner out to the ambient air, possibly via an exhaust filter (not shown) that might be of the Hepa-grade filter type or of any other configuration or filtration grade. During this procedure the valves 36 and 37 are in such positions that they keep the openings to the ambient air closed.

Assuming that the second filter cartridge 32 gets clogged the operator has the possibility to continue the vacuum cleaning operation, as shown in FIG. 2, simply by changing the airflow direction from the second filter cartridge 32 to the first filter cartridge 29. This is effected by changing the position of the valve 24 such that the partially-cleaned air flows from the cyclone outlet 15, through the first section 23 a of the channel 23 via the valve 25, and into the central part of the filter cartridge 29. The air then flows through the filter material and into the first section 35 a of the channel before reaching the fan unit 11.

The operator also has the possibility to clean each filter cartridge in a simple manner by switching the airflow direction in the arrangement. FIG. 3 shows how the second filter cartridge 32 is cleaned. Ambient air is allowed to enter into the system by means of the valve 37. This air flows through a part of the channel section 35 b into the filter space 34 outside the filter cartridge 32 and further through the filter material to the central part of the cartridge 32. Particles that have been clogged at the inside of the filter cartridge 32 are torn away and are taken up by the airflow, and are by means of the valves 26 and 28 distributed through the branched off channel 27 and a part of the channel 18 into the cyclone chamber 13. In order to get sufficient cleaning of the filter there preferably are means, not shown, for concentrating the airflow through the filter to a smaller part of the total filter area such that the air velocity increases through this part. By gradually moving the airflow with respect to the filter surface, for instance by rotating the filter manually or automatically, the complete filter area will be cleaned. From the clean air outlet 15 of the chamber 13, the air then flows through the first section 23 a of the channel 23 into the interior of the first filter cartridge 29 and through the filter material before leaving the first filter space 31 via the first section 35 a of the channel 35 to the fan unit 11. During this cleaning procedure the valve 25 keeps the opening between the first section 23 a and the branched off channel 27 closed and the valve 36 keeps the opening between the first section 35 a and the ambient air closed.

FIG. 4 shows how the first filter cartridge 29 is cleaned in a corresponding way. The operator activates the various valves such that ambient air is now allowed to enter into the system by means of the valve 36. The air flows, in a similar way that has been described above, through the first filter cartridge 29 and the branched off channel 27 into a part of the channel 18 and further into the cyclone chamber 13. The cleaned airflow from the outlet 15 in the cyclone chamber 13 is then directed through the second section 23 b of the channel 23 before entering into the interior of the second filter cartridge 32 where the major part of the remaining particles are separated. After flowing through the filter material the air is directed through the second section 35 b of the channel 35 and further into the fan unit 11.

Thus, the arrangement described above makes it possible to continue a cleaning operation even if the efficiency decreases due to clogging in the filter by simply directing the airflow from the cyclone to another filter. The arrangement also makes it possible to clean the filters without taking them out of the vacuum cleaner simply by activating or deactivating the different valves such that the airflow is shifted in a suitable way. Since the filter cartridges are easy to remove from the vacuum cleaner body it is also easy for the operator to take away the cartridge and clean it more thoroughly in a washing operation if the cartridges are not fully cleaned in the suction operation described above. While the forgoing embodiment shows the filter cartridges 29, 32 as being cylindrical or tube-shaped filters, it will be appreciated that other shapes, such as frustoconical or flat, may be used instead for this and other embodiments of the invention.

FIGS. 5-6 show a diagrammatic representation of a vacuum cleaner comprising another embodiment of the invention. The vacuum cleaner of this embodiment comprises a floor nozzle 49 and a vacuum cleaner body 10. A tube shaft 22 pivotally attaches to the nozzle 49, and a hose 21 connects the tube shaft 22 to the vacuum cleaner body 10. Alternatively, the nozzle may pivotally connect to the vacuum cleaner body, as in an upright vacuum. Dust laden air enters the nozzle 49 and passes through the tube shaft 22 and the hose 21. The dust laden air then enters the vacuum cleaner body and passes through channel 70 and valve assembly 55.

The valve assembly 55 may be moved between a first position, as illustrated by FIG. 5, and a second position, as illustrated by FIG. 6. With valve assembly 55 in the first position, the vacuum cleaner is configured for normal surface cleaning. Dust laden air enters the vacuum cleaner through nozzle 49 and passes through the valve assembly 55 into channel 48. Channel 48 conveys the dust laden air to a dust separation unit 42. Embodiments of the dust separation unit 42 may comprise a cyclone separator having a circular chamber 43 with an inlet 44 for dust laden air and an outlet 45 for partially cleaned air, but a dust bag or non-cyclonic dust box may be used instead. The separation unit 42 may also comprise a dust collecting container 46 connected to cyclone chamber 43 via an opening 47 through which the dust particles are distributed into the container 46. The dust separation unit 42 separates at least a portion of the contaminants from the dust laden air, and partially-cleaned air exits the dust separation unit 42 and passes through channel 50.

The partially cleaned air then passes through a first filter assembly 72. Filter assembly 72 may comprise a first filter space 51 for a first tube-shaped filter cartridge 52 that is removably inserted into said space 51. A central passage 53 of the cartridge 52 communicates via a channel 54 with vacuum source 41 such that air is sucked from the central passage 53 of cartridge 52 to vacuum source 41 and then is directed to the ambient air. The vacuum source 41 may comprise a fan in combination with an electric motor. In a further embodiment, the air passes through a final filter assembly 74 before entering the ambient air.

Referring now to FIG. 6, with valve assembly 55 in the second position, the vacuum cleaner is configured for filter cleaning. The valve 55 prevents dust laden air from flowing through the nozzle 49 and the portion of channel 48 between the valve assembly 55 and the nozzle 49. Rather, ambient air is pulled into and through a filter cleaning assembly 76. Filter cleaning assembly 76 may comprise a second filter space 57 accommodating a second removable, tube shaped filter cartridge 58. A central passage 59 of the cartridge 58 is connected to a passage 60 provided with an inlet opening 61 through which air can be sucked into the filter cartridge in a direction opposite the airflow through first filter assembly 72. After passing through the filter cleaning assembly 76, the air passes through channel 48, through the separation unit 42, and through the filter assembly 72, vacuum source 41, and final filter assembly 74 as in the normal surface cleaning operation.

Embodiments according to FIGS. 5 and 6 operate in the following manner. During normal vacuum cleaning work (see FIG. 5) dust laden air is sucked into the chamber 43 through the nozzle 49 and the channel 48. During this procedure the valve 55 is positioned such that the connection to the channel 56 is closed. Consequently dirt particles are separated in the chamber 43, and are directed into the dust collecting container 46. The air which now has been partially cleaned is sucked through the outlet 45 and the channel 50 to the filter space 51 from which the air flows through the filter material of the cartridge 52 into the central passage 53 of the cartridge. This means that the major part of the particles that have not been separated in the chamber 43 is deposited on an outer surface of the filter material when the air flows through the filter material. Cleaned air then passes into the channel 54 from which it leaves to the ambient air via the fan unit 41 and final filter assembly 74.

When the first cartridge 52 becomes clogged, the operator switches off the vacuum cleaner and exchanges the positions of the two cartridges such that it is possible to continue the work but this time with the clean cartridge 58 in the space 51 and the dirty cartridge 52 in the space 57.

In order to clean the cartridge 52, which is now in the filter space 57, the operator activates the valve 55 such that the connection between the channel 56 and the inlet opening 44 is opened at the same time as the connection to the nozzle 49 is closed (see FIG. 6). Ambient air is now drawn through the opening 60 into the central passage 53 of the cartridge 52 and further through the filter material into the filter space 57.

In this manner, air flows across the filter material of cartridge 52 in an opposite direction to that of normal cleaning. Dust particles on the filter surfaces become free and are transported via the channel 48 to the chamber 43 together with the airflow. The major part of the dust particles are, as mentioned before, separated in the chamber 43 and collected in the container 46 whereas the clean air leaving through the outlet 45 enters the filter space 51, where the air is filtered through the filter material of cartridge 58 before leaving the vacuum cleaner through the channel 54 and the fan unit 41.

According to a further embodiment of the invention it is also possible to use the invention in a conventional cyclone vacuum cleaner that is provided with solely one active filter that is easily removable and that is placed in a filter space connected to the air cyclone and the fan unit. Such a vacuum cleaner can be provided with at least one additional non active filter space serving as a storage place for a passive filter which is easily accessible from the outside of the vacuum cleaner. When the active filter has been clogged during a vacuum cleaner operation the operator can easily remove the active filter from the active filter space and replace it with a cleaned filter that is taken out from the additional filter space. The operator can then finish the cleaning operation and also use the vacuum cleaner for additional cleaning operations before removing the clogged filter and wash or clean it manually. When the filter has been cleaned it is again inserted into the additional non active filter space in order to be used when the active filter has been clogged.

FIGS. 7, 8 and 10 illustrate a canister type vacuum cleaner in accordance with an embodiment of the invention. FIG. 7 is a schematic layout of the embodiment; FIG. 8 is an exploded isometric view of the embodiment; and FIG. 10 is a corresponding isometric view of the embodiment as assembled. A vacuum cleaner body 140 comprises an inlet opening 110 to intake dust laden air. Inlet opening 110 connects to a vacuum cleaner nozzle (not shown) via a hose 111. The inlet opening 110 connects the vacuum nozzle with an inlet channel 112. The inlet channel physically passes between a filter assembly 150 and a filter cleaning assembly 152. Inlet channel 112 comprises a valve assembly 132 adapted to select between air intake through inlet opening 110 and air intake through filter cleaning assembly 152. The valve assembly 132 may be physically positioned between filter assembly 150 and filter cleaning assembly 152.

In the shown embodiment, the filter assembly 150, filter cleaning assembly 152, and valve assembly 132 are positioned generally adjacent each other to form a compact filter module 157. Filter module 157 may comprise a filter module cover 156 extending over an upper end of the filter chamber 150 and filter cleaning chamber 152. The cover may be pivotally attached to the vacuum cleaner body 140.

Inlet channel 112 extends from inlet opening 110 to an inlet 183 of a dust separation unit 154. The dust separation unit 154 is positioned on an upper surface of the vacuum cleaner body 140 rearward of filter module 157. Embodiments of the dust separation unit comprise a handle 444 extending from the separation unit. The handle may be used to manipulate the entire vacuum cleaner body 140 when the dust separation unit is attached to the body. Dust separation unit 154 comprises an outlet 116 communicating with an air passage 117. Air passage 117 fluidly connects dust separation outlet 116 with an inlet 466 of filter assembly 150. The filter assembly comprises a filter chamber 118 in which a first filter cartridge 119A is inserted. Filter assembly 150 may form a portion of filter module 157 and is contained at least partially within vacuum cleaner body 140. Filter assembly 150 is positioned forward of dust collection unit 154 and vacuum source 124. An air passage 123 connects a filter assembly outlet with the air inlet of a vacuum source 124 such as a motor/fan unit. Embodiments of the vacuum source 124 are contained within the vacuum cleaner body 140 and positioned below the dust separation unit 154. The vacuum source exhausts air through a final filter assembly 160 and into the ambient air.

The vacuum cleaner is also provided with a filter cleaning assembly 152 comprising a chamber 125 in which a second filter cartridge 119B, preferably of the same type as the first filter cartridge 119A, is inserted. Filter cleaning assembly 152 comprises an air inlet 129 in communication with the ambient air and an outlet 130, which connects with the inlet channel 112 via an air passage 131 and valve 132. As shown schematically in FIG. 7, the outlet 130 preferably is an elongated slot that extends closely adjacent the surface of the filter 119B. Filter cleaning assembly 152 is positioned along side filter assembly 150 with sufficient spacing to allow inlet channel 112 to pass between the assemblies 150, 152.

FIGS. 7, 8 and 10 together with the accompanying description illustrate the layout of a canister type vacuum cleaner in accordance with an embodiment of the invention. However, other embodiments having different layouts or structures are contemplated. For example, one of skill in the art would recognize that embodiments could be used in conjunction with upright, stick, or other types of vacuum cleaners and systems.

In accordance with embodiments of a vacuum cleaner as illustrated in FIGS. 7, 8 and 10, embodiments of individual elements for use with such a vacuum cleaner are described herewith.

Referring to FIGS. 11-13, a vacuum cleaner in accordance with embodiments of the invention may comprise a floor cleaning assembly 341. The illustrated floor cleaning assembly 341 comprises a power nozzle 300, an extendable wand 301, a handle 340, and a hose 321, but other attachments or variations of these devices may also be used. When using the vacuum cleaner in normal cleaning mode, an operator moves power nozzle 300 across the surface to be cleaned. Power nozzle 300 fluidly and electrically connects with vacuum cleaner body 140 via wand 301, handle 340, and hose 321. Power nozzle 300 may be detachably mounted to wand 301, and the wand may be detachably mounted to handle 340. Handle 340 fluidly connects with hose 321, as illustrated in FIG. 12, and may include a handle guard 342 adapted to receive and store one or more cleaning attachments. The connection between handle 340 and hose 321 may be adapted to allow the hose 321 to rotate with respect to the handle 340.

Referring to FIGS. 10 and 13, hose 321 attaches to vacuum cleaner body 140 by way of cuff assembly 350. Pins 354 extend from the cuff assembly 350 and insert into apertures 352 formed adjacent the inlet opening 110. Apertures 352 contain electrical contacts (not shown) that electrically connect with pins 354, thereby connecting vacuum cleaner body 140 with cuff assembly 350, hose 321, handle 340, and nozzle 300.

Alternatively, other nozzle attachments, such as turbo tools, dusters, and the like, may be used in place of power nozzle 300 and/or wand 301. For example, FIG. 14 shows an attachment in accordance with a further embodiment of the invention. The attachment comprises an extended nozzle 320 or crevice tool. The extended nozzle has a wand portion 322 and a collar portion 324. The wand portion 322 comprises a suction opening 326 for collecting dust from a surface, and the collar portion 324 is adapted to connect to an end of wand 301 or handle 340. The attachment wand portion 322 may have a cross-section that is roughly rectangular or oval and that is narrower in both width and height than the collar portion 324. Extended nozzle 320 further comprises holes or perforations 328 formed in a peripheral wall of the wand portion 322. The perforations 328 maintain cyclone operation and prevent overheating by allowing air to flow through the nozzle, and thus through the entire vacuum cleaner, even when the suction opening 326 is blocked.

Referring now to FIGS. 7-8 and 15-16, the exemplary embodiment of the invention comprises a filter assembly 150, a filter cleaning assembly 152, and a valve 132 for selectively drawing air into the vacuum cleaner through a nozzle 300, 320 for normal surface cleaning or through filter cleaning assembly 152 filter cleaning. In the shown embodiment, these elements are arranged in a filter module 157, but one of skill in the art would readily recognize that the invention is not limited to this arrangement and that other arrangements or combinations may be used. The filter module, the filter assembly 150 and filter cleaning assembly 152 are arranged on either side of the inlet channel 112. The filter assembly 150 comprises a filter chamber 118 with an open top adapted to accommodate a removable filter cartridge 119A. Similarly, filter cleaning assembly 152 comprises a filter cleaning chamber 125 with an open top adapted to receive a removable filter cartridge 119B. The two filters can be conveniently switched between an in-use position (filter chamber 118) and a filter cleaning/storage position (cleaning chamber 125).

The filters 119 may attached to one another to aid in switching the filters 119 between filter chamber 118 and cleaning chamber 125. For example, as shown in FIGS. 8 and 16, a preferred embodiment of the invention may comprise a support structure 121 that engages an upper end of each filter 119, spacing the filters appropriately so that when one filter 119A is inserted into the filter chamber 118, the other filter 119B is correctly positioned in cleaning chamber 125. Support structure 121 allows the user to simultaneously remove and reverse both filters, such that the first filter 119A can be placed in cleaning chamber 125 and the second filter 119B can be placed in filter chamber 118. The support structure 121 preferably includes a handle that also allows the user to avoid touching the filters themselves.

Embodiments of filter cartridge 119 may comprise filters of cylindrical, conical, flat, box or another shape. The filters 119 may also be flat, pleated, multilayer, or have other features known in the art and may have any performance grade, such as HEPA, ULPA, and so on. In preferred embodiments, filter cartridges are cylindrical filters comprising a central channel 120 (FIG. 7) surrounded by a filter element 153. Filter element 153 may be formed of any appropriate material, including paper, fabric, expanded foam or any other material as would be apparent to one of skill in the art. Additionally, the filter element may be pleated.

Each filter cartridge 119 comprises an end cap 155 at an upper end thereof. End cap 155 has a locking extension 170 extending upwardly along a central axis of the filter 119. Locking extension 170 extends through a hole 172 formed in support structure 121 and removably engages a rotatable knob 122, such that each filter 119 is removably connected with support structure 121. Rotating knob 122 rotates filter 119 with respect to support structure 121 and filter chamber 118 or cleaning chamber 125. End cap 155 may also comprise a gasket 177, or other seal, for sealing engagement with filter chamber 118 and/or cleaning chamber 125. For example, the gasket 177 may be disposed around the circumference of the end cap 155 such that it seals the filter chamber 118 or cleaning chamber 125 from communication with the ambient air when filter cartridge 119 is positioned in chamber 118.

The embodiment of FIGS. 8-15 operates similarly to the embodiment of FIGS. 6 and 7. Referring primarily to FIGS. 7, 8 and 15, air enters the device through inlet opening 110 and is conveyed through conduit 112 to the separation unit 154. Upon exiting the dust separation unit 154, partially cleaned air passes through channel 117 leading from the dust separation unit outlet 116 to the filter assembly 150. Embodiments of channel 117 comprise a passageway 410 fluidly connecting dust separation unit outlet 408 (FIG. 22) with a filter assembly inlet 466. Inlet 466 directs air into filter chamber 118. Inlet 466 may be configured to direct air in a tangential flow around a periphery of chamber 118. The incoming, partially-cleaned air passes through filter element 153 in a direction from the outside to the inside. Dust is deposited on an outer surface of filter element 153, and cleaned air passes through central channel 120 and exits filter chamber 118 through outlet 379 into channel 123. Filter chamber 118 may also comprise a gasket 178 surrounding outlet 379 for forming a seal with a lower surface of filter cartridge 119, and a mesh screen to prevent any large objects from being conveyed to the vacuum source 124.

The filter assembly 150 may also comprise an electric circuit connected to a pressure sensor 133 (FIG. 7) for sensing the pressure drop over the filter cartridge 119 in order to indicate when the filter has been clogged. When sensor 133 detects a pressure drop exceeding a preset value, a visual or acoustic signal (e.g., a light or speaker) is activated informing the operator that the filter may be clogged. The operator may then clean the filter utilizing cleaning assembly 152.

With regard to filter cleaning assembly 152, when the vacuum cleaner is in a filter cleaning mode, dust laden air does not enter vacuum body 140 through hose 111 and inlet opening 110. Rather, ambient air enters filter cleaning assembly 152 through inlet 129, passing into central channel 120 of filter cartridge 119B. The air then passes across filter element 153 from inside to outside. As air passes across filter element 153, dust previously deposited on an outer surface of element 153 is removed and carried with the air as the air exits cleaning chamber 125 through an outlet 130. Dust laden air is directed through channel 131 and into valve 132. From valve 132, dust laden air passes through a passage 112 and into dust separation unit 154.

Outlet 130 may be shaped as an elongated narrow opening extending mainly parallel to an axis of filter cartridge 119 and positioned proximate an outer periphery of the cartridge. A narrow opening creates an increased air velocity at outlet 130 improving the filter cleaning efficiency. The filter cartridge 119 may be rotated by knob 122 so that portions of the filter 119 are successively cleaned until the entire filter is clean.

Embodiments of the filter cleaning assembly 152 may also comprise a system for controlling the duration of a filter cleaning cycle. A sensor 134 is arranged proximate cleaning chamber 125, and a permanent magnet 135 is positioned at a periphery of knob 122. When knob 122 begins to turn, sensor 134 detects that passing of magnet 135 and sends a signal to an electric circuit (not shown). The electric circuit turns on vacuum source 124. As the knob 122 and filter cartridge 119 are turned, sensor 134 detects magnet 135 each time the magnet passes the sensor. After a predetermined number of turns have been completed, the electric circuit turns off the vacuum source. Alternatively, a mechanically activated switch may be positioned proximate cleaning chamber 125 to be actuated by a mechanism extending from the filter 119, support structure 121, or knob 122.

For example, FIG. 9 illustrates an example of an embodiment of a system for controlling a filter cleaning cycle using mechanical actuation. An end portion of filter support structure 121 comprises a mainly circular bottom plate 211 with an upwardly extending flange 212, creating a recess 223 in a top surface of the support structure 121. Recess 223 surrounds through hole 172. Knob 122 comprises a rotatable cup shaped cover 213 arranged to cover the recess 223 and through hole 172. Cover 213 comprises an annular element 214 extending from a lower surface of the cover and having a number of outwardly extending fins 215. During rotation of the cover 213, fins 215 will intermittently contact a slider 216 that is linearly and reciprocally movable in an opening 217 in the flange 212. Slider 216 comprises two resilient tongues 218 positioned below cover 213 and resting against the flange 212. Tongues 218 bias slider 216 towards the rotation axis A of the cover 213. As cover 213 rotates, fins 215 and biasing tongues 218 cause the slider 216 to reciprocate. A portion 224 of slider 216 extends outside opening 217 and acts against a switch 219 (see also FIG. 15) connected with the electrical system of the vacuum cleaner. The filter cartridge 119 is placed below the bottom plate 211 and is removably secured to the cover 213 such that filter 119 rotates in unison with cover 213.

In order to clean a filter 119, the operator places a soiled filter in cleaning chamber 125 and starts to turn the cover 213. Fins 215 of cover 213 actuate slider 216 in a reciprocating motion. Slider 216 acts on switch 219, which generates electrical pulses that can be counted by the electric equipment within the vacuum cleaner. After a predetermined number of pulses, vacuum source 124 is activated. As cover 213 is rotated, the periphery of filter element 153 passes elongated outlet opening 130 in cleaning chamber 125. After a predetermined number of pulses, corresponding to a number of complete turns of filter 119, the electric system deactivates vacuum source 124. Alternatively, or in addition, a timer may be used to turn off the vacuum source 124 after a predetermined time has elapsed.

Knob 122 may be turned manually by the operator or may be driven automatically by another electrical or mechanical means such as an electric motor. Additionally, filter cleaning assembly 152 may be arranged such that the vacuum source 124 and the filter 119 rotation start automatically when a dirty filter has been inserted into the filter cleaning chamber 125 and stop after the filter completes a predetermined number of rotations.

Additionally, in order to make the dust removal more efficient, further embodiments of filter cleaning assembly 152 may comprise ridges, brushes, or similar elements extending inwardly from the peripheral wall of cleaning chamber 125, such that dust is wiped from filter element 153 as the element passes the ridges during the rotation of the filter.

As described herein, embodiments of a vacuum cleaner may switch between a normal surface cleaning mode and a filter cleaning mode. In switching between such modes, embodiments of such a vacuum cleaner utilize a valve assembly 132.

Referring to FIGS. 8, 15 and 17-19, embodiments of valve assembly 132 comprise a U-shaped channel 358 and a cover 362. Of course, either of these parts may be integrally formed with other portions or components of the vacuum cleaner. Cover 362 comprises a seal 364 extending around at least a portion of its perimeter. The seal corresponds to a mating surface 367 formed on an upper periphery of the channel 358 so that the channel 358 and cover 362 form a generally airtight passageway forming part of the inlet channel 112 between the inlet opening 110 and the separation unit 154. A portion 380 of the cover 362 extends beyond the channel 358 and covers an adjacent chamber 372. Additionally, one or more apertures 368 extend through a sidewall 370 of the channel 358, fluidly connecting the interior of the channel 358 with chamber 372. Chamber 372 corresponds to passage 131 (see FIG. 7) connecting outlet 130 of cleaning assembly 152 with valve assembly 132.

Referring specifically to FIGS. 17-19, the valve assembly 132 further comprise a valve mechanism 182 (FIG. 17) movable between at least a first position and a second position. The valve mechanism 182 comprises a first valve member 374, a second valve member 376 and an actuating lever 378. The valve mechanism 182 may be pivotally connected with valve cover 362. When the channel 358 and cover 362 are assembled, the first valve member 374 extends below the cover and within the channel 358. The second valve member 376 extends below cover extension 380, along the outside of channel wall 270 and into chamber 372. The actuating lever 378 extends upwardly from cover 362.

FIG. 18 shows a cut-away section of channel 358 with valve mechanism 182 in the first position for normal surface cleaning. In this first position, first valve member 374 extends proximate a lower surface of cover 362, allowing air to pass through the valve assembly 132 from inlet opening 110 to dust separation unit 154 (see FIG. 5). The second valve member 376 covers the apertures 368 in the channel wall 370, preventing air from entering the channel 358 through the apertures 368, and thereby preventing air from passing through filter cleaning assembly 152.

FIG. 19 shows a cut-away section of the channel 358 with valve mechanism 182 in the second position for filter cleaning. In this second position, first valve member 374 extends across the channel 358 blocking air from entering the vacuum cleaner body 140 through inlet 110 (see FIG. 6). The second valve member 376 is repositioned so that it does not cover apertures 368, and air may pass through the apertures, thereby allowing air to be pulled through filter cleaning assembly 152, channel 131 (chamber 372), channel 112 and into dust separation unit 154.

A spring 381 preferably biases the valve mechanism 132 in the second position. A post 379 extends from a lower surface of filter module cover 156. The post 379 contacts actuating lever 378 when cover 156 is closed, moving the valve mechanism 183 from the second position to the first position. In this manner, when cover 156 is open, spring 381 biases valve mechanism 183 into the second/filter cleaning position. When cover 156 is closed, post 379 actuates lever 378 moving valve mechanism 183 into the first/normal surface cleaning position. Accordingly, the operator may switch the vacuum between the surface cleaning mode to the filter cleaning mode by opening and closing filter module cover 156, and the when the operator opens cover 156 to move filters 119, the valve assembly 132 automatically changes to the appropriate mode.

Referring now to FIGS. 7, 8, and 20-25, features of a preferred embodiment of a dust separator unit 154 of the present invention are discussed in detail. As noted previously herein, embodiments of dust separation unit 154 comprise an inlet 183, a cyclonic chamber 113, and an outlet 116. The separation unit 154 may also comprise a dust collecting chamber 115 and an opening 114 through which the dust particles are removed from the cyclonic chamber 113 into the dust collecting chamber 115.

As best shown in FIGS. 8 and 20-25, the dust separation unit 154 comprises a generally cylindrical cyclone chamber 113. An inlet channel 183 directs dust laden air through a side wall of the cyclone chamber in a direction tangential to a wall of the cyclone chamber 113. The inlet channel 183 fluidly connects with the conduit 112 extending from the valve assembly 132.

Referring to FIGS. 20-21, embodiments of the dust separation unit comprise an upper end-cap assembly 384. The upper end-cap assembly 384 comprises a cover 386 and an outlet chamber 388. The cover 386 connects with the outlet chamber to form an outlet passageway 390. A gasket 392 positioned on a lower surface of the cover 386 creates a seal between the cover 386 and an upper edge 394 of the outlet chamber 386 and also creates a seal between the end-cap assembly and an upper edge of the cyclone chamber 113.

The end cap assembly 384 comprises a lower surface 396. The lower surface 396 is elliptically shaped and of a size appropriate to correspond to the inside diameter of the cyclone chamber 113. Therefore, as shown in FIG. 21, the lower surface 396 forms an elliptical cross-section of the cyclone chamber 113, traversing the cyclone chamber at an angle β relative to a longitudinal axis 398 of the cyclone chamber 113. Because the lower surface 396 is elliptically shaped, the angle β will be other than 90 degrees. The rotational orientation of the upper end-cap assembly 384 relative to the cyclone chamber 113 is such that the tangential inlet 183 approximately corresponds to the highest point on the ellipse 400. In this manner, dust laden air entering the cyclone chamber 113 will be directed in a helical motion, circularly around the wall of the cyclone chamber by the tangential nature of the inlet and downwardly by the elliptical shape of the lower surface 396 of the end cap assembly 384. The inlet 183 may be helically shaped to correspond with the shape of the ellipse (i.e. angled along the plane of the ellipse) so that incoming air transitions smoothly between the air inlet 183 and the cyclonic chamber 113, but this is not required. Embodiments may include a gasket 402 around a peripheral edge of the lower surface 396 to seal the lower surface 396 against the inside diameter of the cyclone chamber 113.

Embodiments of the upper end cap assembly 384 further comprise a tubular passageway 404 extending downwardly from the lower surface 396 of the outlet chamber 388. The passageway 404 forms a central outlet for the cyclone chamber 113. A conical grill or perforated shroud 406 may optionally be provided to extend downwardly from a lower end of the tubular passageway 404 and into the cyclone chamber 113. The grill 406 may alternatively comprise a filter such as a cylindrical, radial, or frustoconical pleated filter.

The outlet chamber 388 also comprises a opening 411 formed in a side wall of the outlet chamber. The opening 411 aligns with an outlet channel 408 of the dust separation unit 42. The outlet channel 408 fluidly connects with a passageway corresponding with channel 117 extending from the outlet 116 of the dust separation unit 154 to the filter assembly 150.

The dust separation unit 154 further comprises a dust collecting chamber 115. While the cyclone chamber 113 itself may form or serve as a dust collecting chamber, more preferably, the dust collecting chamber 115 extends along a side wall of the cyclone chamber 113. The dust collecting chamber 115 may be integrally formed with the cyclone chamber, as shown, in which a portion 418 of the cyclone chamber side wall also forms a portion 418 of the dust collecting chamber side wall, or the two chambers may be separately formed. The dust collecting chamber may be of any convenient shape. In a preferred embodiment, the dust collecting chamber has a longitudinal axis parallel to the longitudinal axis 406 of the cyclone chamber 113. As illustrated in FIG. 7, an opening 114 extends between the cyclone chamber 113 and the dust collecting chamber 115 allowing dust to pass from the cyclone chamber into the dust collecting chamber. In the shown embodiment, the dust collecting chamber 115 has an open lower end 420 and a closed upper end 422 (see FIG. 21). The open lower end 420 is covered by a lid assembly 412, as described below. Alternatively, the lower end of the collecting chamber 115 may be closed, and the end-cap assembly 384 formed to cover both the end of the cyclone chamber 113 and the upper end 422 of the dust collecting chamber 115. In this variation, the collecting chamber 115 is emptied by removing all or part of the end-cap assembly 384.

As noted above, the dust separation unit comprises a lower lid assembly 412, which forms a cover for both the lower end of the cyclone chamber 113 and the dust collecting chamber 115. The lid may be generally dish shaped, creating a space 430 between an interior surface 432 of the lid and a lower edge of the cyclone 113 and dust collecting 115 chambers (see FIG. 21). The periphery of the lid assembly 412 corresponds to the periphery of the cyclone chamber 113 and dust collecting chamber 115. A gasket 424 forms a seal between a lower edge of the cyclone chamber 113 and dust collecting chamber 115 and an upper peripheral edge of the lid assembly 412. The matching shapes of the lid assembly 412 and chambers 113, 115 is best shown in FIGS. 24 and 25.

As shown in FIGS. 21 and 25, the opening 114 between the cyclone chamber 113 and the collecting chamber 115 may be formed in the lid assembly 412. A stub wall 426 may extend from the interior surface of the lid assembly, forming an extension of the shared wall 418 to provide the correct size for opening 114. Alternatively, the opening 114 may be formed in the shared wall 418, or between the shared wall 418 and the lid 412.

A projection 436 may extend upwardly from the interior surface 432 of the lid 412 along the longitudinal axis 398 of the cyclone chamber 113. A recessed portion 438 of the lid interior surface 432 surrounding the extension 436 may extend some distance 440 below the remaining portion of the interior surface 412. The extension 436 and recessed surface portion 438 aid in creating and maintaining an efficient cyclonic flow within the cyclone chamber 113 and in efficiently expelling dust through opening 428 into the dust collecting chamber 115.

The lid is operable to empty the contents of the collecting chamber 115 and/or cyclone chamber 113. Preferably, the lid 412 is pivotally attached to cyclone chamber 113 or the dust collecting chamber 115. Alternatively, the lid 412 may be pivotally attached to a handle 444 (FIG. 22) extending from the dust separation unit. A lever 446 is attached to or integrally formed with the lid 412. Actuation of the lever 446 opens the lid 412 allowing a user to dispose of any dust collected in the dust separation unit. To empty the chambers, an operator grasps the handle 444 and uses a thumb to actuate the lever 446 and open lid 412. Because the lid covers both the cyclone chamber 113 and the dust collecting chamber 115, both chambers may be emptied in a single operation using only one hand. Of course, separate lids for each chamber may alternatively be used.

In accordance with embodiments of the dust separation unit 154 discussed herein, dust laden air enters the cyclone chamber 113 through inlet 183. The dust laden air is forced in a downwardly helical direction along the interior surface 442 of the cyclone chamber 113 by the tangential shape of the inlet 183 and by the elliptical shape of end cap assembly lower surface 396. At least a portion of the dust contained in the air is expelled from the cyclone chamber 113 through the opening 428 in the lower lid 412 of the dust separation unit. The partially cleaned air returns in a helical flow up through the center of the cyclone chamber. The air passes through the conical grill 406, through the tubular extension 404 and into the outlet passage 390 formed by the outlet chamber 388 and the cover 386. The air then passes through opening 406 formed in a side wall of the outlet chamber 388 and exits the dust separation unit through the exit channel 408.

Referring to FIGS. 23 and 26, the vacuum cleaner body 140 comprises a cradle 448 formed in an upper portion of the body. The cradle 448 is adapted to receive the dust separation unit 154. The dust separation unit 154 is positionable within the cradle 448 such that the longitudinal axis 398 of the cyclone chamber 113 extends horizontally across a the vacuum cleaner body 140 in a transverse direction. When the dust separation unit is in place, a gasket 450 attached to an end of passageway 112 seals against cyclone inlet 183 to fluidly connect the dust separation unit 154 with the valve assembly 132. A gasket 452 attached to an end of passageway 117 seals against cyclone outlet 408 to fluidly connect the dust separation unit 154 with the filter assembly 150. The dust separation unit securely attaches to the vacuum cleaner body by any suitable arrangement. In the shown embodiment, tabs 454 extend from the dust separation unit and engage recesses 456 formed in the cradle 448 of the vacuum cleaner body 140. A latch assembly 458 in the cradle releasably captures a tab 460 extending from the dust separation unit. Projections 462 may also be formed on the dust separation unit to engage recesses 464 formed in the cradle 448. In this manner, the dust separation unit 154 is securely attached to the vacuum cleaner body 140, and the handle 444 may be used to manipulate the entire vacuum cleaner body 140.

Referring back to FIG. 7, air exiting the dust separation unit 154 passes through the filter assembly 150, as described above, and then passes through vacuum source 124. The vacuum source inlet connects with filter assembly outlet 379 via passage 123, as shown in FIG. 7. The vacuum source 124 comprises a fan assembly driven by an electric motor, as are known in the art. As shown in FIG. 8, the vacuum source 124 may also include foam or other insulation 165, 167, a shroud 166, a gasket 168, a housing 163, and a base plate 164. Foam insulation 165 wraps around motor 169. Foam insulation 167 surrounds shroud 166, being positioned between and interior surface of housing 163 and an exterior surface of shroud 166. Shroud 166 directs the airflow against the inside, front wall of housing 163. The airflow then passes around shroud 166 and exits through the rear of housing 163. Accordingly, shroud 166, foam insulation 167, and housing 163 form a foam-lined circuitous path to reduce airflow noise. Passage 123 and cleaning chamber inlet 129 may be integrally formed with base plate 164.

Air exiting vacuum source 124 passes through an optional final filter assembly 160 comprising a filter element 175 and a cover 173. The filter element 175 may comprise a HEPA filter, or any other filter grade material, and may be formed as a pleated filter, a slab filter, a concave filter, or with any other shape. The final filter assembly 160 may also comprise additional filter elements that stack together to form a multi-layered filter as will be apparent to one of skill in the art. The filter cover 173 itself includes a perforated surface having a number of holes 174, slots, or other openings that allow airflow, but preferably also protect the filter 175 from damage.

Embodiments of a vacuum cleaner as described herein are used in the following manner. When the operator starts the vacuum cleaner dust laden air is sucked in through the hose 111 and the inlet channel 112 to the cyclone chamber 113. Since the inlet flow is arranged to be tangential to the mainly cylindrical cyclone chamber 113 a vortex is created and the particles are, due to centrifugal forces, thrown towards the periphery of the cyclone chamber 113 and out through the opening 114 into the dust container 115 where they are collected. The partially-cleaned air flows through the outlet 116 of the cyclone chamber 113 into the air passage 117 and continues into the filter chamber 118 where the air reaches the first filter cartridge 119A. Smaller particles that have passed the cyclone chamber are now separated in the filter material of the first filter cartridge 119A and the air then flows via the central channel 120, to the motor/fan unit 124, which forces the air through filter element 175 and into the ambient air.

After a period of use, the first filter 119A may become clogged. Pressure sensor 133 will detect a drop in pressure across filter 119A, and a visual and/or acoustic signal will indicate to the operator that the filter is clogged. The operator can now switch off the vacuum cleaner and open the cover 156 of the filter module 157. The filter module cover 156 is connected to the valve 132 such that the valve closes the outer part of the inlet channel 112 and opens up the connection between the inner part of this channel and the air passage 131. The operator then lifts the support structure 121 to which the first and second cartridge 119A, 119B are secured and turns it 180 degrees about a mainly vertical axis before putting the first filter cartridge 119A into the filter cleaning chamber 125 at the same time as the second filter cartridge 119B is inserted in the filter chamber 118.

The operator then manually turns the knob 122 thereby starting to rotate the filter cartridge 119A such that the permanent magnet 135 influences the sensor 134, or the reciprocating slider actuates switch 219, creating a signal starting the motor/fan unit 124. Fresh air is now sucked in from the ambient air through the air inlet 129 and into the central channel 120 of the cartridge 119A. The air then flows through the portion of the filter element facing the narrow outlet 130 with great velocity thereby releasing the dust particles that have been taken up previously and carrying them via the passage 131 and the inner part of the inlet channel 112 to the cyclone chamber 113. The major part of the particles are separated and collected in the dust container 115 whereas the cleaned air leaves through the outlet 116 and flows to the filter chamber 118 via the air passage 117.

The air is then sucked through the filter element 153 and remaining particles are taken up by the second filter cartridge 126 before the air leaves to atmosphere via the air channel 123 and the motor/fan unit 124. When the operator has finished a predetermined number of complete turns of the knob 122 the motor/fan unit is stopped indicating that the filter has been cleaned. The operator now closes the cover which means that the valve 132 is moved back to its original position and the operator can again start the vacuum cleaner and continue his work. When the second filter cartridge 126 has been clogged the procedure described above will be repeated thereby switching the two filter cartridges 119,126 back to their original positions. 

1. A vacuum cleaner dust separation unit comprising: a cyclone chamber (113) extending along a longitudinal axis (398) and having an air inlet (183), an air outlet (408), an inlet wall (396) between the air inlet (183) and the air outlet (408), and one or more air passages (404) through the inlet wall (396); and a dust collection chamber (115) adapted to receive dirt from the cyclone chamber (113); characterized in that the inlet wall (396) comprises an elliptical wall that is located adjacent the air inlet (182) and angled relative to the longitudinal axis (398).
 2. The vacuum cleaner dust separation unit of claim 1, wherein the cyclone chamber (113) comprises an elongated chamber having an end wall (432) located opposite the inlet wall (396), the end wall (432) comprising a recessed portion (438) surrounding an extended portion (436) that protrudes into the cyclone chamber (113).
 3. The vacuum cleaner dust separation unit of claim 1 or 2, wherein the cyclone chamber (113) comprises a dirt outlet (114) located at an end of the cyclone chamber (113) opposite the air inlet (183), and the dust collection chamber (115) is fluidly connected to the dirt outlet (114).
 4. The vacuum cleaner dust separation unit of claim 2, wherein the dirt outlet (114) is located on an opposite side of the cyclone chamber longitudinal axis (398) as the air inlet (183).
 5. The vacuum cleaner dust separation unit of claim 2 or 3, wherein the end wall (432) comprises a removable lid (412).
 6. The vacuum cleaner dust separation unit of claim 5, wherein the lid (412) comprises a cavity that forms the dirt outlet (114).
 7. The vacuum cleaner dust separation unit of claim 5, wherein the removable lid (412) is pivotally attached to the cyclone chamber (113) and dust collection chamber (115).
 8. The vacuum cleaner dust separation unit of claim 3, wherein the dust collection chamber (115) is located adjacent the cyclone chamber (113) in a horizontal plane when the vacuum cleaner dust separation unit is mounted on a vacuum cleaner for use, such that dirt moves in a horizontal direction to pass from the cyclone chamber (113) to the dust collection chamber (115).
 9. The vacuum cleaner dust separation unit of claim 1, wherein the one or more air passages (404) comprises a tubular member that extends from the inlet wall (396) into the cyclone chamber (113) and has one or more openings (406) passing therethrough.
 10. The vacuum cleaner dust separation unit of claim 9, wherein the tubular member terminates at a conical shroud and the one or more openings (406) pass through the conical shroud.
 11. The vacuum cleaner dust separation unit of claim 1, wherein the cyclone chamber (113) comprises a sidewall that extends along the longitudinal axis (398) and an end cap (384) removably attached at one end of the sidewall and adjacent the air inlet (183).
 12. The vacuum cleaner dust separation unit of claim 10, wherein the inlet wall (396) is removable from the cyclone chamber (113) with the end cap (384).
 13. The vacuum cleaner dust separation unit of claim 11 or 12, wherein the air outlet (408) passes through the sidewall, and the end cap (384) comprises an opening (411) that is positioned in fluid communication with the air outlet (408) when the end cap (384) is attached to the sidewall.
 14. A vacuum cleaner dust separation unit comprising: a cyclone chamber (113) extending along a longitudinal axis (398) and having an air inlet (183), an air outlet (408), an inlet wall (396) between the air inlet (183) and the air outlet (408), an end wall (432) located opposite the inlet wall (396), one or more air passages (404) through the inlet wall (396), and a dirt outlet (114) adjacent the end wall (432); and a dust collection chamber (115) fluidly connected to the dirt outlet (114) and adapted to receive dirt from the cyclone chamber (113); characterized in that the end wall (432) comprises a recessed portion (438) surrounding an extended portion (436) that protrudes into the cyclone chamber (113).
 15. The vacuum cleaner dust separation unit of claim 14, wherein the inlet wall (396) comprises an elliptical wall that is located adjacent the air inlet (182) and angled relative to the longitudinal axis (398).
 16. The vacuum cleaner dust separation unit of claim 14, wherein the dirt outlet (114) is located on an opposite side of the cyclone chamber longitudinal axis (398) as the air inlet (183).
 17. The vacuum cleaner dust separation unit of claim 14, wherein the end wall (432) comprises a removable lid (412).
 18. The vacuum cleaner dust separation unit of claim 17, wherein the lid (412) comprises a cavity that forms the dirt outlet (114).
 19. The vacuum cleaner dust separation unit of claim 17, wherein the removable lid (412) is pivotally attached to the cyclone chamber (113) and dust collection chamber (115).
 20. The vacuum cleaner dust separation unit of claim 14, wherein the dust collection chamber (115) is located adjacent the cyclone chamber (113) in a horizontal plane when the vacuum cleaner dust separation unit is mounted on a vacuum cleaner for use, such that dirt moves in a horizontal direction to pass from the cyclone chamber (113) to the dust collection chamber (115).
 21. The vacuum cleaner dust separation unit of claim 14, wherein the one or more air passages (404) comprises a tubular member that extends from the inlet wall (396) into the cyclone chamber (113) and has one or more openings (406) passing therethrough.
 22. The vacuum cleaner dust separation unit of claim 21, wherein the tubular member terminates at a conical shroud and the one or more openings (406) pass through the conical shroud.
 23. The vacuum cleaner dust separation unit of claim 14, wherein the cyclone chamber (113) comprises a sidewall that extends along the longitudinal axis (398) and an end cap (384) removably attached at one end of the sidewall and adjacent the air inlet (183).
 24. The vacuum cleaner dust separation unit of claim 23, wherein the inlet wall (396) is removable from the cyclone chamber (113) with the end cap (384).
 25. The vacuum cleaner dust separation unit of claim 23 or 24, wherein the air outlet (408) passes through the sidewall, and the end cap (384) comprises an opening (411) that is positioned in fluid communication with the air outlet (408) when the end cap (384) is attached to the sidewall. 